Method of constructing ballast resistances



Patented Sept.` ll, 1928;,

*JUNI'Iwsm'ff-sf mm fmwe'.

SAMUEL BUTTENBERG, 'or BxooKLYN, NEW Yonx, Assrenoaro SAMUEL v Ann MEYER NATHAN Lernowrrz, oF nnwjyonm, N. Y.

RUTTENBBBG l METHonoF consfmnc'rme, BALLAST nnsis'rANcEs.

Application led Mayk m3,

fvThis invention relates` to a method of windingy Wire or'the like lfor use `as electri cal resistancesl v f 'y f In 'endeavoring'y to obviate the necessity of using 'batterieslin yconnection with Wireless receiving sets, it nhas'been proposed to conneetfthe setrthrough suitablevmeans to the elect-ricy current mains. Onelobjection tol such an arrangement, however, especially in country district/@fis that the voltage of I the supply vmains is liable to vary to quite an appreciable extent. It is'necessary, ofv course,'if'the ap aratus is to operate succefssfully,y thatv t e impressed voltage .be

order'to obtain such a constant voltage, it has ybeen proposed to usere'sistances in the input circuitfwhichwill varyfin value jaccording to the strength of, the current fiowing 'therethroughfin such a manner as to give 'a' substantially uniform voltage at the terminals thereof.y

Such lresistancesy referred to in the art as ballast f resistances, though they areintended for heavy duty, should be neonstructed so that they illvas small a space as f possible, and so that there will be no liabilityof sliort-circuitin j taking place vbetween various' rts thereo l One o.v thefobjects ofthe present invention is to provide a method of winding such resistances on a .formfin an expeditious manner." i i A further object of the `invention is to provide a method of winding resistances in spiral form bywhich thedi'ameterfof the Youter peripheral "surface thereof is made uniform and the different spirals thereof separated from each otherv yby denite amounts. y j y Afurther object of the invention is to provide a 'method of Winding ballast resistances ivhichareespecially adapted for malr- 'infry up in cartridge form, i.`e. in tubes of cylindrical form having contacts vat the two ends. Y f i .fccording to vthis invention, the resistance Wire lor ythe like is wound upon a form made l ofinsulating material, and ofv a` substan- `tiallyk flat formation, by enclosing the body of such formivithin'a'core or theilikewiththe edges of suchorm Vextending beyond thesurface of such core, and Winding the t resistance Wire or' thelile on said core 'in maintained substantially constant, and in 192s. seran No, 106,291'f l serrations vor slots Within ythe proiecting edges of such' form.

In orderth'at the invention maybeclearly i a formr used ,v Figure 6 is affrontI relevation of the core y and form shown in Figurey 5, having the resistance 'Wire Wound thereon' i' i j Figure 7 shows a resistance made according tothis invention, assembled'in cartridge form. Y y v y The form 1 is made of any suitable insulating materiah but preferably ,of mica, and is preferably of flat formation. as shown inFigure 2 of the drawing. Such formation, however, is not essential7 but, if desired, it may be vof narrow elliptical form or other suitable shape. Y t i The two side edgesjot' the form, as is clearly shown in Figure l of the drawing,

are serrated, being respectively' provided with series fof slots 2 and 3, the slots in one `edge being preferably odset With respect to those in the other edge,

The core about which the resistancewire is to be wound may be of metal, Wood, or other suitable material', and comprises a member 4 of a length somewhat greater than the form llaandV 0f a cross-section depending upon the shape into which it is desired to Wlnd kthe resistance.y

The resistances preferably are Wound into a' cylindrical form, and in such case the crosssection of the corey willr be circular. Extending longitudinally of the core, from plone end thereof, and to a distance slightly greater than the length of the form 1, is a slot 5, as shown in FiguresB and 4 of the drawingQl The slot is of a shape adapted to receive the form l, andin the embodiment .illustratedis ofv rectangular form, as shown in Figure 4; of the drawing. The diameter of the core in the direction of the slot 5 is substantially equal to the distance between the bases of the two rows of slots 2 and 3 in the form, so that, when the form is placed in position within the core7 the edges of the form will project beyond the sides of the core distances equal substantially to the depth of the slots therein.

The wire to be used for the resistance may be of iron or other suitable material, haring a fairly high temperature coefficient of resistance.

After the form is placed in position within the core, with the serrated edges projecting therefrom, the wireA is wound around the core, as shown in Figure G-of the drawing, being passed through the slots in such projecting edges. Thus, if the core t is of circular cross-section, the wire will form a resistance 6 of spiral form, with all the coils of the same diameter, and spaced apart equal distances.

In order to facilitate the removal of the wound wire and the forni l from the core, the core is preferably slightly tapered, the tapering being towards the open end of the slot Also, in order to prevent the two halves of the core being caused to grip the form too tightly during the winding operation, the' spacedk portions of the core at the cud thereof may be held in proper spaced relationby means of a member 7 (as shown in dotted lines in Fig. 5) which is of a thickness slightly greater than that of the form, and which may be placed within the open end of the slot 5 after the introduction therein of the form l. Such member 7 may, if desired, be integral with one or other half of the core, and, in order to facilitate the introduction of the form within the core, one or other of such halves of the core may be hinged or pivoted at its rear end to the body of the core. y

lllhen removed from the core, the coils of the resistance G will be maintained in the desired' spaced relation by means of the form l. in the slots of which such resistance is wound. The distance apart of these slots will, of course, determine the distance between the adjacent coils of the resistance. A. suitable distance between the slots is from 31- to if of an inch, and the depth of such slots is preferably greater than the diameter of wire to be wound therein.

The resistance, after being wound on the insulating form, may be mounted in any suitable manner. preferably being int-roduced into a bulb containing hydrogen or other inert gas. and its opposite ends connected to two terminals. A preferred form of tube for supporting the resistance is illustrated in Figure 7 of the drawing, this tube being of cylindrical form, and liaying terminals 9 at the opposite ends thereof, to

which the ends of the coiled resistance are attached.

The ientral port-ion of the tube S between the terminals 9 is preferably of glass, and `he terminals 9 are in the form of caps covering the open endsY of such tube. The internal diameter of the tube is very slightly greater than the width of the form, so that the form with the resistance wound thereon Amay be introduced therein; such form,'be ing of insulating material, may rest against the inner surface of the tube, and since the slots in the side edges of the form are of greater depth than the diameter of the resistance wire, such wire will be spaced apart from the inner surface of the tube. The advantage of a tube of this form is that it takes up a minimum of space, and that it can be readily mounted by placing it in position between two spring terminals lO-10.

The form and core described in this specication are described by way of example only, and it is obvious, of course, that these may vary both as to shape and asto material without departing from the spirit and scope of theinvention, as defined in the accompanying claims.

I claim l. The method of winding resistance wire on a form of substantially fiat shape having serrated edges with the coils of said wire supported in said serrations, but otherwise spaced from the form, which consists in supporting said form within a core with its serrated edges projecting from the sides thereof, and winding said wire on said core between the serrations on the side edgesof the form.

2. The method of winding resistance wire on aV form of substantially lflat shape having serrated edges with the coils of said wire supported in .said serrations, but otherwise spaced from the form, which consists in supporting said form within a longitudinally extending slot within said core, with its serrated edges projecting from the sides thereof, and winding said wire on said core between the serrations on the side edges of the form.

3. The method of winding resistance wire on a form of substantially fiat shape hai'- ing serrated edges wit-h the coils of said wire supported in said serrations, but otherwise spaced from the forni, which consists in supporting said form within a core of the shape of the resistance which it is desired to wind, with its serrated edges projecting from the sides thereof, and winding said wire on said core between the serrations on the side edges of the form.

. The method of winding resistance wire on a form ofsubstantially fiat shape having serrated edges with the coils of said wire supported in said serrations, but otherwise spaced from the form, which consists in supi [porting saidform within a `rcore slightly core between the serratons on the side edges of the form. n

5. The method of Winding resistance Wire ona form of substantially flat shape hay ing series of 'slots in the side edges thereof respectively, which consists in supporting said form Within a Core With its edges projecting from the sides thereof distances substantially equal to the depth of the slots', and Winding saidvwire on said core Within said slots on the side edges of the form. Y

' In testimony whereof I affix my signature.

. SAMUEL RUTTENBERG. 

